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linux/drivers/hwmon/ina2xx.c
Bartosz Golaszewski f975b3399c hwmon: (ina2xx) bail-out from ina2xx_probe() in case of configuration errors 
The return value of i2c_smbus_write_word_swapped() isn't checked in
ina2xx_probe(). This leads to devices being registered even if they cannot
be physically detected (e.g. device is not powered-up at boot-time).

Even after restoring power to such device, it is left unconfigured as the
configuration has never been actually written to the register.

Error out in case of write errors in probe and notify the user.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
[Guenter Roeck: Fixed multi-line comment style]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-11-30 20:13:14 -08:00

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/*
* Driver for Texas Instruments INA219, INA226 power monitor chips
*
* INA219:
* Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
* Datasheet: http://www.ti.com/product/ina219
*
* INA220:
* Bi-Directional Current/Power Monitor with I2C Interface
* Datasheet: http://www.ti.com/product/ina220
*
* INA226:
* Bi-Directional Current/Power Monitor with I2C Interface
* Datasheet: http://www.ti.com/product/ina226
*
* INA230:
* Bi-directional Current/Power Monitor with I2C Interface
* Datasheet: http://www.ti.com/product/ina230
*
* Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
* Thanks to Jan Volkering
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/of.h>
#include <linux/platform_data/ina2xx.h>
/* common register definitions */
#define INA2XX_CONFIG 0x00
#define INA2XX_SHUNT_VOLTAGE 0x01 /* readonly */
#define INA2XX_BUS_VOLTAGE 0x02 /* readonly */
#define INA2XX_POWER 0x03 /* readonly */
#define INA2XX_CURRENT 0x04 /* readonly */
#define INA2XX_CALIBRATION 0x05
/* INA226 register definitions */
#define INA226_MASK_ENABLE 0x06
#define INA226_ALERT_LIMIT 0x07
#define INA226_DIE_ID 0xFF
/* register count */
#define INA219_REGISTERS 6
#define INA226_REGISTERS 8
#define INA2XX_MAX_REGISTERS 8
/* settings - depend on use case */
#define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */
#define INA226_CONFIG_DEFAULT 0x4527 /* averages=16 */
/* worst case is 68.10 ms (~14.6Hz, ina219) */
#define INA2XX_CONVERSION_RATE 15
enum ina2xx_ids { ina219, ina226 };
struct ina2xx_config {
u16 config_default;
int calibration_factor;
int registers;
int shunt_div;
int bus_voltage_shift;
int bus_voltage_lsb; /* uV */
int power_lsb; /* uW */
};
struct ina2xx_data {
struct i2c_client *client;
const struct ina2xx_config *config;
struct mutex update_lock;
bool valid;
unsigned long last_updated;
int kind;
u16 regs[INA2XX_MAX_REGISTERS];
};
static const struct ina2xx_config ina2xx_config[] = {
[ina219] = {
.config_default = INA219_CONFIG_DEFAULT,
.calibration_factor = 40960000,
.registers = INA219_REGISTERS,
.shunt_div = 100,
.bus_voltage_shift = 3,
.bus_voltage_lsb = 4000,
.power_lsb = 20000,
},
[ina226] = {
.config_default = INA226_CONFIG_DEFAULT,
.calibration_factor = 5120000,
.registers = INA226_REGISTERS,
.shunt_div = 400,
.bus_voltage_shift = 0,
.bus_voltage_lsb = 1250,
.power_lsb = 25000,
},
};
static struct ina2xx_data *ina2xx_update_device(struct device *dev)
{
struct ina2xx_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
struct ina2xx_data *ret = data;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated +
HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
int i;
dev_dbg(&client->dev, "Starting ina2xx update\n");
/* Read all registers */
for (i = 0; i < data->config->registers; i++) {
int rv = i2c_smbus_read_word_swapped(client, i);
if (rv < 0) {
ret = ERR_PTR(rv);
goto abort;
}
data->regs[i] = rv;
}
data->last_updated = jiffies;
data->valid = 1;
}
abort:
mutex_unlock(&data->update_lock);
return ret;
}
static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
{
int val;
switch (reg) {
case INA2XX_SHUNT_VOLTAGE:
/* signed register */
val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
data->config->shunt_div);
break;
case INA2XX_BUS_VOLTAGE:
val = (data->regs[reg] >> data->config->bus_voltage_shift)
* data->config->bus_voltage_lsb;
val = DIV_ROUND_CLOSEST(val, 1000);
break;
case INA2XX_POWER:
val = data->regs[reg] * data->config->power_lsb;
break;
case INA2XX_CURRENT:
/* signed register, LSB=1mA (selected), in mA */
val = (s16)data->regs[reg];
break;
default:
/* programmer goofed */
WARN_ON_ONCE(1);
val = 0;
break;
}
return val;
}
static ssize_t ina2xx_show_value(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ina2xx_data *data = ina2xx_update_device(dev);
if (IS_ERR(data))
return PTR_ERR(data);
return snprintf(buf, PAGE_SIZE, "%d\n",
ina2xx_get_value(data, attr->index));
}
/* shunt voltage */
static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
INA2XX_SHUNT_VOLTAGE);
/* bus voltage */
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
INA2XX_BUS_VOLTAGE);
/* calculated current */
static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
INA2XX_CURRENT);
/* calculated power */
static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
INA2XX_POWER);
/* pointers to created device attributes */
static struct attribute *ina2xx_attrs[] = {
&sensor_dev_attr_in0_input.dev_attr.attr,
&sensor_dev_attr_in1_input.dev_attr.attr,
&sensor_dev_attr_curr1_input.dev_attr.attr,
&sensor_dev_attr_power1_input.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(ina2xx);
static int ina2xx_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct ina2xx_platform_data *pdata;
struct device *dev = &client->dev;
struct ina2xx_data *data;
struct device *hwmon_dev;
long shunt = 10000; /* default shunt value 10mOhms */
u32 val;
int ret;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
if (dev_get_platdata(dev)) {
pdata = dev_get_platdata(dev);
shunt = pdata->shunt_uohms;
} else if (!of_property_read_u32(dev->of_node,
"shunt-resistor", &val)) {
shunt = val;
}
if (shunt <= 0)
return -ENODEV;
/* set the device type */
data->kind = id->driver_data;
data->config = &ina2xx_config[data->kind];
/* device configuration */
ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
data->config->config_default);
if (ret < 0) {
dev_err(dev,
"error writing to the config register: %d", ret);
return -ENODEV;
}
/*
* Set current LSB to 1mA, shunt is in uOhms
* (equation 13 in datasheet).
*/
ret = i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
data->config->calibration_factor / shunt);
if (ret < 0) {
dev_err(dev,
"error writing to the calibration register: %d", ret);
return -ENODEV;
}
data->client = client;
mutex_init(&data->update_lock);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data, ina2xx_groups);
if (IS_ERR(hwmon_dev))
return PTR_ERR(hwmon_dev);
dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
id->name, shunt);
return 0;
}
static const struct i2c_device_id ina2xx_id[] = {
{ "ina219", ina219 },
{ "ina220", ina219 },
{ "ina226", ina226 },
{ "ina230", ina226 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ina2xx_id);
static struct i2c_driver ina2xx_driver = {
.driver = {
.name = "ina2xx",
},
.probe = ina2xx_probe,
.id_table = ina2xx_id,
};
module_i2c_driver(ina2xx_driver);
MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
MODULE_DESCRIPTION("ina2xx driver");
MODULE_LICENSE("GPL");
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